The invention generally relates to partial radio block detection.
Wireless mobile stations, such as cellular handsets (as an example), transmit and receive information, including representations of speech waveforms, in radio frequency (RF) waves. A physical layer of a cellular handset typically includes circuitry for performing two major functions, namely encoding and decoding. This circuitry typically includes a channel codec for performing channel encoding and decoding functions and a vocoder for performing voice encoding and decoding functions. The vocoder performs source encoding and decoding on speech waveforms. Source coding removes redundancy from the waveform and reduces the bandwidth (or equivalently the bit-rate) in order to transmit the waveform in real-time. The channel codec increases redundancy in the transmitted signal to enhance the robustness of the transmitted signal against channel imperfections.
A number of different wireless communication protocols, such as the global system for mobile communications protocol (called “GSM”), employ error correction coding, such as forward error correction (FEC). Communication systems that employ error correction coding may generally use a two-stage receiver architecture that includes an equalizer and a decoder. The function of the equalizer is to undo adverse channel effects, and the function of the decoder is to recover original data bits from the encoded sequence.
Modern communication systems may also use an interleaving scheme to avoid large gaps in the received data if the channel conditions degrade temporarily. After deinterleaving, degraded data symbols are spread among a large number of reliable symbols, allowing the decoder a chance to correctly decode the degraded symbols. In many applications, data is transmitted and received in finite-length packets or bursts. Interleaving in such systems is done over multiple bursts, and hence decoding occurs after a certain number of bursts have been received. For example, in a GSM system data is interleaved over a range of 4 to 22 bursts, depending on the logical channel in use. The equalizer, on the other hand, generally works on each burst separately.